Over the past 7 years, the mechanisms by which Staphylococcus aureus, an infectious microorganism, adheres to host tissues has been studied because adherence is the first step in the development of an infection. If bacteria are unable to adhere to a surface, they will be swept away by the body fluids that normally bathe the tissues and an infection will not occur. Hence, adherence is the crucial first step in initiating and spreading infections. It is generally accepted that microorganisms adhere to surface components of the host tissues.
It has been found that S. aureus interacts with a host protein called "fibronectin." Fibronectin is a major component of the material found between cells and also in blood plasma. Fibronectin is essential to the well-being of the host as it serves as the "glue" which links one cell to another cell and plays a major role in wound healing.
There are several lines of evidence which suggest that fibronectin plays an important role in the adherence of S. aureus to host tissues. Supporting this concept are the following observations: (i) S. aureus has a specific receptor for fibronectin,.sup.* (ii) the S. aureus fibronectin receptor (FN-R) is expressed on the surface of the bacterium where it can interact with host tissues,.sup.* (iii) the fibronectin receptor is expressed in greater numbers on clinical isolates of S. aureus that have invaded the host as compared to noninvasive isolates,.sup.* (iv) purified FN-R decreases S. aureus interactions with fibronectin,.sup.* (v) antibodies directed against FN-R reduce fibronectin binding to S. aureus,.sup.* (vi) fibronectin is found at sites frequently infected by S. aureus, (vii) fibronectin enhances S. aureus adherence,.sup.* (viii) specific removal of fibronectin from a complex mixture of host proteins decreases S. aureus binding while removal of other proteins does not, and (ix) antibodies against fibronectin inhibit S. aureus binding to host tissues.
There also are data which suggest that the fibronectin receptor polysaccharide plays a major role in the initiation of S. aureus infections: (i) S. aureus mutants that are isogenic with the parent strain except for the ability to express fibronectin receptor colonize the heart valves of rats 120-fold less effectively than the parent strain.sup.* and (ii) a monoclonal antibody which recognizes the most invasive strains of S. aureus interacts preferentially with the fibronectin receptor..sup.* FNT .sup.* Discovered in R.A. Proctor's laboratory
My article "The Staphylococcal Fibronectin Receptor: Evidence for Its Importance in Invasive Infections" in Reviews of Infectious Diseases Vol. 9, Supp. 4, .sctn.335 to .sctn.340 (July/August 1987) reviews the data that support the presence of a specific fibronectin receptor on S. aureus and discusses the criteria necessary to establish a role for fibronectin in pathogenesis of invasive staphylococcal infections.
The above article is incorporated by reference herein.